ABSORB is a program for Windows to calculate and apply absorption corrections to X-ray intensity data from any source and any detector type (lab or synchrotron, point detector or area detector). Corrections can be made for spherical crystals, and crystals with regular or irregular shapes, and for the effects of absorption and gasket shadowing from diamond-anvil pressure cells. It will handle Rfine and Shelx datafiles. ABSORB-7 first released in July 2012 contains several significant new features. It includes ABSORB-GUI (shown above), written by Javier Gonzalez-Platas (Universidad de La Laguna, Tenerife) which allows much easier specification of standard experiments. The program that does the absorption calculations was re-configured to allow it to be called directly from other software as well. ABSORB-7 and ABSORB-GUI can be installed by downloading and running this self-installer. This installs both the Absorb program and the GUI. If you have previously installed Absorb-7, first uninstall the old version and then delete the ABSORB environment variable from the system. We recommend that you install the programs in a separate folder, and not in the folders where you work on data. Do NOT install in a system folder like C:\Program Files (x86)\ as this may cause you problems. The installer will create two sub-folders. One folder has the full users' manual and copies of the publications that describe the program, and the other folder has some example files. Programmers and users who do not need the GUI can download the latest version of Absorb-7 and the manuals as a zip file without the GUI. This includes the programmers' guide with information on how to call and interact with the ABSORB program from other software. If you download and use ABSORB, please register with us by e-mail, so that we can inform you of new releases and updates of the software. The ABSORB program itself is described in J. Appl. Cryst. 37, 486-492 which is also available here. Copyright © International Union of Crystallography. If you use ABSORB-7 and/or ABSORB-GUI please cite Angel RJ, Gonzalez-Platas J (2013) Absorb-7 and Absorb-GUI for single-crystal absorption corrections. J. Appl. Cryst. 46, 252-254 which is also available here. Copyright © International Union of Crystallography. Last Update: Version 7.30 (February 2024). This replaces the previous version 7.20, and includes some minor bug fixes: Fixed handling of smallbeam case in DAC to eliminate false error messages. Fixed reading of hkl files with incommensurate data by determining the format directly when reading the file into Absorb. If you are using either a development version or version 7.2, please upgrade to this version. If you use Absorb from within the Crysalis software from Rigaku Oxford Diffraction, you do not need to install the new version of Absorb separately. It is included in Crysalis from versions 43.119a and 44.45a.